{"id":"CVE-2026-52939","state":"PUBLISHED","title":"net/rds: fix NULL deref in rds_ib_send_cqe_handler() on masked atomic completion","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/rds: fix NULL deref in rds_ib_send_cqe_handler() on masked atomic completion\n\nrds_ib_xmit_atomic() always programs a masked atomic opcode\n(IB_WR_MASKED_ATOMIC_CMP_AND_SWP or IB_WR_MASKED_ATOMIC_FETCH_AND_ADD)\nfor every RDS atomic cmsg.  But the completion-side switch in\nrds_ib_send_unmap_op() only handles the non-masked opcodes, so a masked\natomic completion falls through to default and returns rm == NULL while\nsend->s_op is left set.  rds_ib_send_cqe_handler() then dereferences the\nNULL rm via rm->m_final_op, oopsing in softirq context.  An unprivileged\nAF_RDS sendmsg() of an atomic cmsg over an active RDS/IB connection\ntriggers it; on hardware that natively accepts masked atomics (mlx4,\nmlx5) no extra setup is needed.\n\n  RDS/IB: rds_ib_send_unmap_op: unexpected opcode 0xd in WR!\n  Oops: general protection fault [#1] SMP KASAN\n  KASAN: null-ptr-deref in range [0x0000000000000190-0x0000000000000197]\n  RIP: rds_ib_send_cqe_handler+0x25c/0xb10 (net/rds/ib_send.c:282)\n  Call Trace:\n   <IRQ>\n   rds_ib_send_cqe_handler (net/rds/ib_send.c:282)\n   poll_scq (net/rds/ib_cm.c:274)\n   rds_ib_tasklet_fn_send (net/rds/ib_cm.c:294)\n   tasklet_action_common (kernel/softirq.c:943)\n   handle_softirqs (kernel/softirq.c:573)\n   run_ksoftirqd (kernel/softirq.c:479)\n   </IRQ>\n  Kernel panic - not syncing: Fatal exception in interrupt\n\nHandle the masked atomic opcodes in the same case as the non-masked\nones: they map to the same struct rds_message.atomic union member, so\nthe existing container_of()/rds_ib_send_unmap_atomic() body is correct\nfor them.","publishedAt":"2026-06-24T07:14:28.622Z","updatedAt":"2026-06-24T07:14:28.622Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"20c72bd5f5f902e5a8745d51573699605bf8d21c","status":"affected","lessThan":"a0148342badd8c9b2e46551766a27cb76c82e715","versionType":"git"},{"version":"20c72bd5f5f902e5a8745d51573699605bf8d21c","status":"affected","lessThan":"4dd262f875e87653df50b138de1390ab0628e6b7","versionType":"git"},{"version":"20c72bd5f5f902e5a8745d51573699605bf8d21c","status":"affected","lessThan":"6e4615164d185a26badb2f376a2449f4d174a5f0","versionType":"git"},{"version":"20c72bd5f5f902e5a8745d51573699605bf8d21c","status":"affected","lessThan":"0f22412a2f4fbbe0251c132abee045d15a90e5b6","versionType":"git"},{"version":"20c72bd5f5f902e5a8745d51573699605bf8d21c","status":"affected","lessThan":"0f7baa82a24813cdad0b06a6f8f07e4824af5ed5","versionType":"git"},{"version":"20c72bd5f5f902e5a8745d51573699605bf8d21c","status":"affected","lessThan":"dcf458120add64c96a6ef5cf719340453f6e6abf","versionType":"git"},{"version":"20c72bd5f5f902e5a8745d51573699605bf8d21c","status":"affected","lessThan":"4fd34669558085bcb589aa2078a13b0ca79e360d","versionType":"git"},{"version":"20c72bd5f5f902e5a8745d51573699605bf8d21c","status":"affected","lessThan":"34080db3e70ddf94c38512ad2331e3c3afca6cc1","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/rds/ib_send.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.37","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.37","versionType":"semver"},{"version":"5.10.259","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.210","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.176","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.143","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.94","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.36","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.13","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/rds/ib_send.c"]}],"references":["https://git.kernel.org/stable/c/a0148342badd8c9b2e46551766a27cb76c82e715","https://git.kernel.org/stable/c/4dd262f875e87653df50b138de1390ab0628e6b7","https://git.kernel.org/stable/c/6e4615164d185a26badb2f376a2449f4d174a5f0","https://git.kernel.org/stable/c/0f22412a2f4fbbe0251c132abee045d15a90e5b6","https://git.kernel.org/stable/c/0f7baa82a24813cdad0b06a6f8f07e4824af5ed5","https://git.kernel.org/stable/c/dcf458120add64c96a6ef5cf719340453f6e6abf","https://git.kernel.org/stable/c/4fd34669558085bcb589aa2078a13b0ca79e360d","https://git.kernel.org/stable/c/34080db3e70ddf94c38512ad2331e3c3afca6cc1"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:16.098Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/52xxx/CVE-2026-52939.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-52939","state":"PUBLISHED","datePublished":"2026-06-24T07:14:28.622Z","dateUpdated":"2026-06-24T07:14:28.622Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-06-09T07:44:35.370Z"},"containers":{"cna":{"title":"net/rds: fix NULL deref in rds_ib_send_cqe_handler() on masked atomic completion","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/rds: fix NULL deref in rds_ib_send_cqe_handler() on masked atomic completion\n\nrds_ib_xmit_atomic() always programs a masked atomic opcode\n(IB_WR_MASKED_ATOMIC_CMP_AND_SWP or IB_WR_MASKED_ATOMIC_FETCH_AND_ADD)\nfor every RDS atomic cmsg.  But the completion-side switch in\nrds_ib_send_unmap_op() only handles the non-masked opcodes, so a masked\natomic completion falls through to default and returns rm == NULL while\nsend->s_op is left set.  rds_ib_send_cqe_handler() then dereferences the\nNULL rm via rm->m_final_op, oopsing in softirq context.  An unprivileged\nAF_RDS sendmsg() of an atomic cmsg over an active RDS/IB connection\ntriggers it; on hardware that natively accepts masked atomics (mlx4,\nmlx5) no extra setup is needed.\n\n  RDS/IB: rds_ib_send_unmap_op: unexpected opcode 0xd in WR!\n  Oops: general protection fault [#1] SMP KASAN\n  KASAN: null-ptr-deref in range [0x0000000000000190-0x0000000000000197]\n  RIP: rds_ib_send_cqe_handler+0x25c/0xb10 (net/rds/ib_send.c:282)\n  Call Trace:\n   <IRQ>\n   rds_ib_send_cqe_handler (net/rds/ib_send.c:282)\n   poll_scq (net/rds/ib_cm.c:274)\n   rds_ib_tasklet_fn_send (net/rds/ib_cm.c:294)\n   tasklet_action_common (kernel/softirq.c:943)\n   handle_softirqs (kernel/softirq.c:573)\n   run_ksoftirqd (kernel/softirq.c:479)\n   </IRQ>\n  Kernel panic - not syncing: Fatal exception in interrupt\n\nHandle the masked atomic opcodes in the same case as the non-masked\nones: they map to the same struct rds_message.atomic union member, so\nthe existing container_of()/rds_ib_send_unmap_atomic() body is correct\nfor them."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"20c72bd5f5f902e5a8745d51573699605bf8d21c","status":"affected","lessThan":"a0148342badd8c9b2e46551766a27cb76c82e715","versionType":"git"},{"version":"20c72bd5f5f902e5a8745d51573699605bf8d21c","status":"affected","lessThan":"4dd262f875e87653df50b138de1390ab0628e6b7","versionType":"git"},{"version":"20c72bd5f5f902e5a8745d51573699605bf8d21c","status":"affected","lessThan":"6e4615164d185a26badb2f376a2449f4d174a5f0","versionType":"git"},{"version":"20c72bd5f5f902e5a8745d51573699605bf8d21c","status":"affected","lessThan":"0f22412a2f4fbbe0251c132abee045d15a90e5b6","versionType":"git"},{"version":"20c72bd5f5f902e5a8745d51573699605bf8d21c","status":"affected","lessThan":"0f7baa82a24813cdad0b06a6f8f07e4824af5ed5","versionType":"git"},{"version":"20c72bd5f5f902e5a8745d51573699605bf8d21c","status":"affected","lessThan":"dcf458120add64c96a6ef5cf719340453f6e6abf","versionType":"git"},{"version":"20c72bd5f5f902e5a8745d51573699605bf8d21c","status":"affected","lessThan":"4fd34669558085bcb589aa2078a13b0ca79e360d","versionType":"git"},{"version":"20c72bd5f5f902e5a8745d51573699605bf8d21c","status":"affected","lessThan":"34080db3e70ddf94c38512ad2331e3c3afca6cc1","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/rds/ib_send.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.37","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.37","versionType":"semver"},{"version":"5.10.259","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.210","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.176","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.143","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.94","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.36","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.13","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/rds/ib_send.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/a0148342badd8c9b2e46551766a27cb76c82e715"},{"url":"https://git.kernel.org/stable/c/4dd262f875e87653df50b138de1390ab0628e6b7"},{"url":"https://git.kernel.org/stable/c/6e4615164d185a26badb2f376a2449f4d174a5f0"},{"url":"https://git.kernel.org/stable/c/0f22412a2f4fbbe0251c132abee045d15a90e5b6"},{"url":"https://git.kernel.org/stable/c/0f7baa82a24813cdad0b06a6f8f07e4824af5ed5"},{"url":"https://git.kernel.org/stable/c/dcf458120add64c96a6ef5cf719340453f6e6abf"},{"url":"https://git.kernel.org/stable/c/4fd34669558085bcb589aa2078a13b0ca79e360d"},{"url":"https://git.kernel.org/stable/c/34080db3e70ddf94c38512ad2331e3c3afca6cc1"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-06-24T07:14:28.622Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.37","versionEndExcluding":"5.10.259"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.37","versionEndExcluding":"5.15.210"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.37","versionEndExcluding":"6.1.176"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.37","versionEndExcluding":"6.6.143"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.37","versionEndExcluding":"6.12.94"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.37","versionEndExcluding":"6.18.36"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.37","versionEndExcluding":"7.0.13"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.37","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}